Semiconductor devices having an integrally molded case and lead frames wherein the lead frames are directly soldered to semiconductor chips to draw electric current have been disclosed (see, for example, PTL 1).
Semiconductor devices that use ribbon bonds for drawing electric current have also been disclosed (see, for example, PTL 2). The ribbon bonds are members that undergo a bending process during the process of being bonded to semiconductor elements. Since the ribbon bonds can be made thicker only to a limited extent, a plurality of ribbon bonds need to be connected in order to achieve a certain current to be conducted, which causes the device to be bulky. Lead frames, on the other hand, are obtained by forming plate materials having a cross-sectional area corresponding to a current to be conducted, into a desired shape by stamping and bending before the process of connecting the lead frames to semiconductor elements, and are connected to the semiconductor elements with a solder material, for example. A single lead frame is used for one or more semiconductor elements to draw electric current.
A semiconductor device having main terminals for drawing electric current provided vertically in the center has been disclosed (see, for example, PTL 3). This semiconductor device does not allow a control circuit to be directly connected thereabove. Bus bars are therefore necessary to draw electric current from the semiconductor device to the outside for connection with a control substrate, because of which the number of constituent parts and the device size are increased. The main terminals are set vertically for guaranteeing insulation and it is a common structure in high voltage products having a breakdown voltage of 1,700 V or more, for example. The necessity to guarantee insulation, however, makes it hard to provide control terminals in close proximity. Semiconductor devices for automobiles are driven by batteries mounted inside the automobile and they only need to have a breakdown voltage of not more than 1,400 V. Since such semiconductor devices do not require the high voltage design concept mentioned above, the main electrodes are extended out to the outside of the control terminals of the semiconductor device. Therefore, a control substrate can be attached directly to the semiconductor device and electric current can still be input and output to and from the semiconductor device.